A motor is used as a source of power in a precision stage, a semiconductor manufacturing equipment, an outdoor unit of air conditioner, a refrigerator and other different types of appliances. When a motor starts rotating, initial torque is generated at the start up. In a typical motor, the torque is received at the motor base, but the motor base is usually separated from the central axis of rotation. For this reason, when the torque develops at the startup of the motor, a reaction torque centered around the position of mounting of the motor base acts on the motor in addition to its self-rotational torque, and the problem of vibration of the motor arises.
When vibration of the motor is taken into account, the moment can be considered as an integral moment of inertia of the rotor of the motor and the rotating load connected to the rotor. If the torque of the motor is τ, the moment of inertia is I and angular velocity is α; then the following equation holds true according to the second law of motion.τ=Iα
Thus, for rotating the motor with angular velocity α, a torque τ acts on the rotor and the rotating load of the motor, and a reaction torque-τ acts on the motor base, where the motor is located. This torque-τ, which acts on the motor base, causes vibration of the motor and the motor base.
For solving this problem, various methods such as increasing the rigidity of the motor base and inserting shock-absorbing materials (see for example, Patent Document 1) have been adopted.
Non-Patent Document 1 has disclosed a magnetic gear mechanism for transferring the torque outputted from the motor.
[Patent Document 1] Japanese Patent Application Laid-Open No. H3-4048
[Non-Patent Document 1] Ikeda Tetsuya, Nakamura Kenji, Ichinokura Osamu ‘A Way to Improve Efficiency of Permanent-Magnet Magnetic Gears’, Jikigakkai ronbunshi, 2009, Vol. 33, No. 2, Page. 130-134.